


Small Packages

by marykathryn30



Category: Captain America - All Media Types
Genre: Alpha Bucky Barnes, Alpha Tony Stark, Alpha/Beta/Omega Dynamics, Bucky Barnes Needs a Hug, Domestic Avengers, M/M, Mating Cycles/In Heat, Omega Steve Rogers, Post-Captain America: The Winter Soldier, Smut, steve rogers is an idiot
Language: English
Status: Completed
Published: 2019-09-18
Updated: 2019-09-18
Packaged: 2020-10-21 07:08:02
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 8,054
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/20689505
Author URL: https://archiveofourown.org/users/marykathryn30/pseuds/marykathryn30
Summary: “Friday, call Pepper,” he said, watching Steve curl his knees into his chest and fold himself into a neat little ball. “See if there’s any way we can get Barnes back from that mission early.”“Russian times zones are a little complicated, sir,” Friday happily chirped back. “But I’ll see what I can do.”“What’s wrong with him?” Sam demanded, wings collapsing in on themselves as he stuttered to a landing next to them.“It’s, uh, he’s in heat,” Tony said blandly.Or Steve goes into an early heat and Bucky rushes home to an unexpected surprise.





	Small Packages

“We-,”  _ clang  _ “Are-,”  _ clang  _ “Very-,”  _ clang  _ “Not clear!” Steve growled into the coms, launching his shield at the attacking aliens between every word. Goddamn Stark and his goddamn experiments in the lab that opened  _ another portal  _ to  _ another unknown universe,  _ spitting out hundreds of blue-green, six eyed aliens, apparently content to do nothing but scream and rip their way through Harlem. 

“Where you at, Cap?” Sam asked, the sounds of his guns thudding dully in the background. 

“By the bank,” he snarled, driving the edge of his shield into another one of the things chest. Thick black goo spat from the wound and drenched his uniform and face and hair. He’d lost the cowl about a half hour ago, his scalp itching and tingling under the minimal added pressure. It normally wasn’t enough to set him off, but he guessed his mood was bad enough he wanted to kill these fuckers as Steve Rogers and not Captain America. “You closed that fucking portal yet, Stark?” 

“Jesus Christ, watch your fucking language,” Tony tsk’d and Steve let a growl rip from between his lips. “Calm down, Capsicle. I got it closed and I’m flying to you now.” 

“About time.” 

“Someone is in a mood,” Natasha said. Steve heard an unholy squelch from her end and winced. 

“What’s the matter, Bucky Bear not put out before he left for the Motherland?” Tony teased and Steve seriously debated splitting his own skull with his shield.

“Can we not talk about my sex life over the comms?” Steve growled, wiping sweat off his forehead as he surveyed the dead creatures around him. 

“What else is there to talk about?” 

“Fuck off, Tony.” 

“Ooh, you got first named by Cap. You’re in trouuuble.” 

“You can fuck off, too, Clint.” 

“Aww, man.” 

Nat’s amused snort at Cint’s whining was cut short by an enormous boom from the center of the city, followed by slightly muffled screaming and the sound of glass shattering. 

“Any idea what that could be, Tony?” Nat asked cooly. 

“Uhh, really big firecracker?” 

“Or maybe, I don’t know, a fucking queen alien smashing her way through town hall?” Sam said, sarcasm thick in his throat, and Steve groaned. He just wanted to fucking go home and shower. And now they had to kill a fucking queen alien. Lovely. 

“Oh, look,” Nat said. “She’s making more weird alien things. And these ones have pincers, cool. Aaaand they’re heading into the streets. We evacuated civilians, right?” 

“Yes,” Steve grunted, picking his shield up with a sigh and jogging towards the middle of the city. “Clint, Sam, keep the perimeter. Don’t let them get too far into the city or we’ll lose them. The rest of us will converge on the queen, see if we can focus on getting her out of the way before we deal with the others.” 

“We need to call a code green?” Tony asked. “I’ve got Bruce on speed dial.” 

“Let’s see what we’re dealing with before we call in the big guy.” 

“Wish Barnes was here so he could just stick his metal arm up the queens ass so she stops pooping babies.” 

“The only ass that arm is going up is Steve’s,” Tony said, and Steve made an indignant noise. “That technology is too expensive to use on alien assholes. You heard him, arrows. Keep the perimeter. That means go over there. Away from me.” 

“But I thought we were buddies, Stark.” 

“Barton. Go.” Tony pulled his alpha voice out, his voice dropping an octave or two and filling with an authority Clint, an omega, couldn’t ignore.

“Ooh, heads up guys. Queen bug face is still shitting, and she just smashed half of some diner. How far out is everyone?” 

“Coming up on the queen now,” Steve said, raising his shield and grunting as one of the aliens launched itself at him, all six arms trying desperately to claw at his face. He beat his way through a throng of them, scanning the area around him as he panted for air. 

“Bad guys heading your way, Sam,” he gasped, wiping his forehead before squaring his shoulders and turning to face the queen, who was currently occupied with crashing through an apartment building. “We’re clear here except for the queen. I’m going in.” 

“Hey, no, bad idea,” Tony said. “I’m less than five from you, Cap, just sit tight and kill whatever babies she’s popping out.” 

“I’ve got a clear line now, Stark,” he grunted, already running towards the queens back. “I’ll scream if I need back up.” 

“We have no idea what she’s capable of, Steve,” Sam said, always the voice of reason. 

“Bird brain’s right,” Clint added. “For once. You’ve don’t have a clue what you’re up against, Stevie.” 

“Only one way to find out.” 

He grit his teeth and threw the shield, the disk slicing through the air to connect with the side of the queen’s neck with a resounding  _ clang;  _ she staggered to the side, turning to face him as he drew back to level a punch to her face. She beat him to it, though, swinging out one of her nine arms and clipping his legs out from under him, baring three rows of slobbery, yellowed teeth. He kicked up at her from his position on the ground, hissing as she threw the entire left side of her body into his gut, knocking the wind out of him. Ripping his head to the side, she dragged a thin, bumpy green finger across the scent glands in his neck, pinning his arms and legs down with her multitude of arms. Her neck tilted to the side as he thrashed, a thick clicking noise rising out of her throat before her finger stabbed into his glands, ripping through his bond mark and sinking deeper as blood gushed around the digit. 

He barely registered his roar of pain, the whir of Stark’s arc reactor as he blew the queen back, her hand ripping from Steve’s neck with a wet glide. Turning on his side, he held a shaking hand to his neck, whimpering, and fumbling for his shield with the other hand. The queen was screaming as she took on Stark, knocking him through a building and dropping a glittery triangle device onto the ground, rainbow shards of light reflecting on the rubble around them. 

Steve had a moment to be confused before the triangle expanded, other triangles slapping onto the pavement in a geometric pattern until the area it covered was about the size of a manhole cover. And more aliens started to climb out of the triangles as it glowed pale blue and hummed. 

“If we survive this,” he groaned, forcing himself onto his knees and coughing wetly. “Stark, ‘m gonna kill you.” 

“Are you gonna sit there and threaten me, or are you gonna help me kill these things?” Tony responded, dropping to the pavement and firing his blasters at the small army climbing out of the ground. The squeal of tires announced Nat’s arrival, a gun in each hand as she folded herself gracefully out of the sports car she’d hotwired, already firing. 

“You good, Cap?” she asked, kicking his shield to his hands. 

He nodded and made his aching body move, fighting through the fog clouding his brain to get to his feet; he swayed on his feet a little, stumbling into Nat and brushing her off when she shot him a concerned look. 

“I’m fine,” he snarled, picking up his shield and weakly blocking an attack from one of the aliens. He struggled to lift the weight of the shield, his chest heaving, arms straining just to keep himself protected, let alone put him on the offensive. Sweat dripped into his eyes, an unfamiliar ache settling into his bones, his legs shaking as he forced himself to stay upright. He was vaguely aware of the face his neck hadn’t stopped bleeding, the wound still open and gushing, something the serum should’ve taken care of. 

The aliens must have noticed his weakness, a slew of them abandoning their position on Stark to crowd him, mouths open and snapping. Their hands, so many green hands, pulled the shield from his grasp and flung it away and his body, his enhanced, super soldier body, just dropped, his knees clattering to the pavement, the aliens surrounding him at all sides. Some grabbed at his neck, smearing blood on his skin and uniform, others ripping at the kevlar and fabric, tearing at his skin and hair and limbs. 

Nat and Tony worked together to free him, Nat snapping necks with one arm, the other still firing her gun, while Tony blasted what he could. 

“Cap,” Tony said, offering a hand up. Steve just blinked up at him, his blue eyes clouded and unfocused, and Tony tried his best not to panic. “Come on, Steve. Up ya go, big guy.” 

Tony reached out and gripped his shoulder, trying to help him stand, and Steve right out whined at the touch of the metal suit against his uncovered skin. There was an Alpha behind that glove, an Alpha with a knot and a breeding instinct and the ability to make him submit. Another whine slipped out of his throat, high and needy, and Tony visibly recoiled. 

The mystery pain plaguing his body turned into something much more familiar, his muscles loosening, his entire body going pliant, his omega instincts taking over and forcing the burn of a heat into his veins. His skin started to prickle, like a thousand white hot needles poked into every one of his pores, his body wriggling of its own accord, needing out of the pressing confines of his shredded suit. Clothes were too much, the scent of the two alpha’s in front of him was too much, the sun hitting his skin was too much. Too much, not enough, he couldn’t figure it out. 

Tony and Nat both stared and took a step back as the scent of a needy omega in heat reached them, Tony’s jaw dropping in disbelief. None of them except Bucky had seen Steve in heat. Hell, the blonde usually locked himself on their floor at the first sign of pre heat and they wouldn’t see him again until it’d completely passed. Steve was sure Bucky had explained it to them, when Clint and Sam had expressed some concern over his secrecy, that Steve didn’t want his team to see him in such a submissive state, that he thought they’d see him as less of a leader. Which was bullshit. No one gave a damn if he was an omega. Clint, Sam, and Pepper were all omega’s; they all had heats, and it didn’t change the way anyone saw them. But Steve was nothing if not stubborn, and so he kept up his streak of hiding any signs of a heat, anything that would brand him as an omega. 

Tony snapped his faceplate back over his face and visibly straightened his stance, helping Steve to the ground while the blonde shuddered and started to whine. 

“Friday, call Pepper,” he said, watching Steve curl his knees into his chest and fold himself into a neat little ball. “See if there’s any way we can get Barnes back from that mission early.” 

“Russian times zones are a little complicated, sir,” Friday happily chirped back. “But I’ll see what I can do.”

“What’s wrong with him?” Sam demanded, wings collapsing in on themselves as he stuttered to a landing next to them. The rest of the team started to gather, all with varying degrees of worry for their captain. 

“It’s, uh, he’s in heat,” Tony said blandly. Sam’s dark eyebrows came together. 

“That’s not possible,” he said slowly. “Cap’s on more suppressants than the rest of us combined.” 

“One, I don’t want to know how or why you know that. Two-,” 

“It was the queen,” Steve hissed through gritted teeth. He raised his face, skin tinted red and dripping sweat, and blinked at them through cloudy eyes. He moved onto his hands and knees, coughing up a wet glob of blood that splattered onto the pavement below him. “Uck. She- something with my glands, fucked with my cycle.” 

“Makes sense,” Nat said, stooping down to help him stand. “An omega in heat attracts all the alphas and makes other omegas skittish. It’s a good strategy.” 

Steve grunted his assent and leaned weakly on Sam as the man ducked under his arm to keep him upright. 

“Fuck, you’re heavy,” he complained, elbowing Steve jokingly in the ribs; the blonde grunted, his eyebrows drawing together into the middle of his forehead. 

“Gonna-,” he choked out, before hunching over, leaning as best he could away from Sam, and vomiting. 

“Cute,” Tony said, and Sam glared at him. 

“This isn’t right,” Steve gasped, putting his hands on his knees and fighting to not collapse. “Heats aren’t- ain’t like this.” 

“He’s going Brooklyn on us,” Tony said, waving his arms dramatically. “Somebody call a chaplain.” 

The team turned to collectively glare at him as Steve retched again. 

“Sorry, my stand-up isn’t as charming as usual,” he said, rolling his eyes and helping Sam support Steve. “Blame it on Capsicle stinking up the whole street.” 

“Fuck you,” Steve wheezed. 

“Yeah, you’d like that. Friday, you got a jet for us? As much as I’d love to sweep Cap off his feet, something tells me his Comrade might not like that so much.” 

“Already left the compound, sir,” she said, at the same time Steve legs crumpled underneath him and sent him sagging towards the ground. 

“Okay, big guy, here we go,” Sam said, working with Tony to lower Steve to a sitting position on the spot of the ground not covered in alien guts and puke. “What’s our plan?” he asked, looking at the rest of the team. 

“Obviously we have to call Barnes,” Nat said, folding her arms. “He’s not- this isn’t a normal heat.” 

“And what are we gonna tell him?” Tony asked, gesturing broadly towards Steve. “Hey, Bucko, we know you just left for a super classified Winter Soldier redemption mission and made all of us take secret oaths to watch out for your mate, but we kinda let him go off on his own and now he’s a little fucked up and needs knotted.” 

At the mention of a knot, Steve let out another unholy whine, shifting in his spot on the ground and bringing his knees up so he could drop his face into them. 

“Sorry,” he whispered hoarsely. Nat just reached down to sympathetically pat his sweaty head. 

“I don’t think we should call Barnes until Bruce has had a chance to look him over,” Clint said, and he flipped Tony the middle finger when the man looked shocked. “He’s gonna be pissed and have a ton of questions. Better to have the answers he wants instead of fumbling around and making him more mad.” 

“And here we were, ready to kick Barton out of the group for not having brains,” Tony said. Clint rolled his eyes and grumbled a response that was quickly drowned by the roar of the jet lowering towards them. It landed smoothly, the loading bay hissing open. Bruce jogged out with a stretcher and a tired looking Helen Cho. 

“Not what we were expecting your visit to be, Helen,” Tony said apologetically as him and Sam helped heft Steve onto the stretcher. 

“I’ve grown to expect the unexpected,” she said brightly, offering him a quick smile as they all loaded the jet. Bruce made quick work of securing the stretcher while Clint moved to the controls, settling comfortably in the pilot’s seat and waiting for Bruce’s go-ahead before taking off. 

“How we feeling, Steve?” Bruce asked, circling his fingers around Steve’s wrist and keeping an eye on the ticking hand of his watch. 

Steve just groaned incoherently. 

“His temperature’s rising,” Helen said, frowning at the thermometer in her hand. 

“Yeah, and his pulse is almost triple what it should be,” Bruce said. “Friday, can you have fluids and an IV ready for us? Clear out section C of the med wing, and get Steve’s normal vitals on hand so we know what we need to get him back down to.” 

“Anything else, boss?” 

Bruce glanced up and hesitated, eyes flickering from Tony to Nat, who were both shifting uncomfortably. 

“Make sure we clear the med bay of any Alphas,” he said slowly, swiping the trash can off the floor in time for Steve to try to throw up his insides. Tony grimaced and slid his faceplate shut again and Nat just took a few polite steps to the front of the cockpit, tugging her glove off with her teeth and running a thumb over the scarred bite mark on the side of Clint’s neck. 

The next twenty minutes were a haze, Tony and Natasha booking it out of the jet with equally guilty expression while Bruce wheeled Steve out and to the med bay. 

“Alright, Steve, I’m gonna need you to help me a little,” he said, hurriedly rolling his sleeves up and moving to do the same to Steve’s uniform, the needle of the IV between his fingers. “I’m gonna need you to tell me what you’re feeling right now.” 

“Like shit.” 

“Yeah, well, I guessed that. Got anything more clinical than that?” He spread the thin Irish skin of Steve’s wrist to follow the vein up his arm, inserting the IV and setting it up quickly. 

“S’like a normal heat,” Steve groaned, his head rolling lazily to the side to blink blearily at Bruce. “But worse. Dunno.” 

“Fatigue? Shakiness? All your normal symptoms?” 

Steve nodded and wiped a shaking pale hand across his forehead. Sam came in then, shortly followed by Clint, both of them radiating nervous energy. The minute the med doors hissed open, they both took an automatic half step back, the smell of charcoal and fresh peaches almost overwhelming. Clint wrinkled his nose. 

“Never knew I’d figure out what Cap sounds like on the rag,” he said, sniffing a little and leading the way into the room. 

“He’s not on the rag,” Bruce corrected, fumbling with his glasses as Helen setup Steve’s heart rate monitor; it immediately started blipping off the charts, high and fast even for Steve’s heart. “That’s a sexist and out of date expression.” 

Clint just shrugged and Sam rolled his eyes. 

“You figured out what’s wrong with him?” he asked as Bruce carefully leaned over to inspect the still bleeding wound on Steve’s bonding mark. He frowned, wrinkles creasing thickly on his forehead. 

“When did you get this?” he asked, ignoring Sam and yanking on a pair of gloves. 

“Shortly before we got him on the jet,” Sam said after a few moments of Steve groaning incoherently. “Maybe five minutes before we boarded.” 

“That’s not right.” Bruce carefully put pressure on either side of the perfectly round gouge, pushing just a little and frowning harder when a bead of purple-blueish liquid beaded near the center and dribbled down the side of Steve’s neck. 

Steve, who’s heart rate suddenly rocketed, his chest rising from the table until his spine was entirely off the steel before he dropped back with a grunt. Bruce jumped back and everyone froze except Steve, who grit his teeth and tried not to whine when he felt a fresh gush of slick seep into his uniform. That was going to be a stain he wasn’t going to be able to get out. 

“Okay, so we’re not doing that again,” Bruce said, swiping up the goo with a scalpel and depositing it into a small metal tray. 

“Thanks,” Steve hissed through his teeth. 

“Hey, you’re coherent enough to be a dick. That’s a good sign.” Clint clapped him on the shoulder and he winced. 

“F’ck  _ off _ .” 

“You two take this to Tony,” Bruce said, sliding the pan into a biohazard bag and sealing it. He held it out to Clint, who made no move to take it from him and blinked owlishly until Sam huffed and took it. “Get him running tests on that and somebody call Barnes before he starts feeling it in their bond mark and kills us all for not keeping him updated.” 

The entire medbay could smell the sudden sourness of fear in the two omegas as they scurried to Tony’s lab. 

…….

Something was wrong. Very, very wrong. 

Bucky scowled at the blurry video feed of the team shifting their feet like little kids caught coloring on the walls; he took a slow, even breath through his nose and rubbed impatiently at the dull throb in his wrist. His mark, his sweet permanent indent of his Stevie’s pretty teeth on the inside of his right wrist, hadn’t stopped pounding for the last couple hours. 

And now the team was looking guilty and sheepish. 

“What happened?” he growled, pressing his metal thumb into the mark Steve’s right canine had made in his skin. 

Three sets of eyes flickered to Tony, who shifted nervously on his feet and avoided the camera. 

“Stark,” Bucky snarled, leaning forward in his chair, eyebrows low over his dark eyes. Send him to Russia for a month long mission and he’s not even gone two weeks and somebody fucked something up. Probably his mate, but that wasn’t the point right now. 

Tony flinched, hackles automatically raising defensively before he huffed and crossed his arms. 

“We need your location.” 

“Classified.” 

“Thanks, dipshit,” Tony snapped, rolling his eyes. “If it wasn’t classified, I would’ve sent the jet already.” 

“Not supposed to be home for another three weeks, Stark.” 

“Yeah, well.” Tony flapped his arms frustratedly and glared at his team. “You’re coming home early. Congrats. You can come back to civilization and everything.” 

“What happened?” Bucky asked, voice low and dark. Something was wrong, potentially wrong with  _ Steve  _ and Stark fucking around was starting to piss him off. 

“Well, it’s- I mean, he’s fine but-,” 

_ “What happened?”  _ He ripped the full timber of his alpha voice out, rising in his seat slightly, the aggression in his face enough to make Stark instinctively bare his teeth and Natalia glower at him. 

“A portal to some other dimension got opened in New York,” Wilson said, stepping forward and nudging Stark out of the way. “A queen came through and your boy tried to take her on single handed, got himself hurt with some sort of toxin that messed with his cycle and sent him into heat early.” 

_ Oh, his poor baby. _ Bucky dropped back into his seat, a little deflated. He could picture it, Steve all flushed and hot, whining and desperate for a knot, for anything to soothe the cramps and hormones. 

“Steve’s been through heats alone before,” he said slowly, eyebrows coming together in his forehead. Everyone on the screen shifted nervously. “When I had that no contact mission in Siberia.” 

“That- yeah, he did.” 

“So you’re not telling me something.” 

“Or we just wanted to let you know your mate was in heat, since we could actually contact you this time.” 

Bucky just raised a disbelieving eyebrow in Clint’s direction and the omega instantly crumbled, hunching his shoulders and stepping back from the camera, mumbling quietly to himself. 

“This heat’s a little different,” Sam said slowly, like he was tasting each word carefully before saying it. “It’s hard to explain. But you need to come back.”

“Different how?” 

“It’s- we’ll let you see when you get here. He’s not dead, he’s not dying, just needs his mate. Okay?” 

He blew a slow breath out his nose and rubbed at the silvery scar of his mating mark. 

“When’s the jet coming?” he asked after rattling off his coordinates, reaching for the silenced handgun sitting on the table next to his laptop. Stark poked at his keyboard for a couple of seconds, a dent between his eyebrows, before settling back with a strained smile. 

“Looks like it’ll be at your location in just over three hours. Then three hours back, so you’ll be back and ready to screw ole’ Stevie into oblivion before the evening news.” 

Bucky made a point to show Stark him closing his click into the bottom of the gun before standing. 

“Alright.” He swiped his kevlar off the back his chair and strapped it on, running over the logistics in his head.  _ Mission location: 43.1198° N, 131.8869° E. Back bedroom has a loose window lock, two targets- no captives, no witnesses. _

“We’re not telling Steve we called you,” Natalia said quietly, and Bucky’s head jerked up. 

“Why not?” 

“He damn near went into cardiac arrest when we brought up the idea,” Wilson said. He folded his arms and looked almost defiantly into the camera. “Said he wouldn’t be the reason for stopping your Hydra hunt.” 

_ Sounds like Stevie. Self-sacrificing dumbass.  _

Bucky rolled his eyes and blew out a huff, reaching for the top of the laptop. 

“Just keep him safe until I get there. Okay?” 

The team nodded, sharing a few semi-nervous glances but nodding nonetheless. Bucky took it for what it was and closed the laptop with a snap, holstering his guns and working through his weapons checklist before marching out the door. 

  
  


Three and a half hours later had him shedding his kevlar in the back of an unmanned jet, wiping blood splatter from his cheek with a mango scented baby wipe.

  
  


Seven hours had him stomping off the jet to an eerily quiet landing pad. Alright, maybe no one wanted to face the Winter Soldier post-mission with a distressed mate. 

But then the entire hangar was empty. And the hall leading out to the common areas. 

He stopped in the main floor common area, the hair on the back of his neck prickling. The space barely held a smell, meaning everyone that’d been here had left a while ago. No sign or smell of the team or Steve. His right hand twitched towards the hand gun strapped to his thigh. 

“Mr. Stark sent everyone in the compound home for the day,” a soft masculine voice said from his left. 

Bucky turned and bared his teeth, yanking the gun from it’s leather home and growling low in the back of his throat. 

A growl that stopped abruptly when he found himself face to face with Vision, who just smiled politely at him. Well, that explained the lack of warning pheromones. 

“Jesus, Vis,” he grumbled, lowering the gun and running his fingers through his hair. “Warn a guy.” 

“With all respect, Sergeant Barnes, I do believe it was you who found different ways to travel the compound without being seen and then popping out in front of a certain bird-themed Avenger.” 

“Ahh, but that shit’s funny.” He grinned and Vision just shook his head minutely. 

“If you’ll follow me,” he said, turning and heading towards the elevators. “Mr. Stark has set up an observation area in one of the older labs.” 

Bucky slowed his steps, frowning a little at Vision’s back. 

“I’m going to see Steve,” he said, not moving as Vision turned back around. 

“You will. The team found it important to update you on Captain Rogers’ condition before you meet with him, in case something were to be… triggering.” 

“Triggering,” he said flatly, and Vision sighed. 

“It’s been ten hours since Captain Rogers returned to the compound, injured, and, though his condition has not worsened, it also hasn’t improved. Ten minutes of explanation will not kill him, I assure you. It’s much safer this way.” 

_ Safer.  _ The word bounced around in his brain like an over-inflated balloon, knocking shit off the shelves and making him itchy and defensive. He wasn’t a danger, especially not to Steve. Not anymore. He’d put a bullet in the back of his throat before he got close to hurting his mate. Again. Bile burned at the memory of Steve splayed out underneath him, bloody and riddled with bullets from the Winter Soldier’s gun, choking on mucus and blood that they’d be together till the end of the line. 

“I- fine. Let’s go.” 

“Finally, Robo-Cop hath arrived!” 

“Where the fuck is my mate, Stark?” 

Stark visibly paled, his scent souring just a little with stress. The whole room stank of a heady mix of alphas and omegas, like none of them had left the room for a while. A wall of monitors sat on one of the examination tables, thick black and blue cables winding every which way, in and out of a series of computers. Bucky recognized one constantly feeding out Steve’s vitals and felt his stomach drop at how uneven and hurried that heartbeat was. 

“His heart usually runs a little fast,” Banner said, stepping next to him and nodding towards the screen. “And the heat is speeding everything up. Which is also why his temperature is so high. I refilled his IV about an hour ago, help keep him hydrated. He’s too weak to sit up and drink on his own, and he’s been throwing up everything we tried to give him.” 

Bucky got the overwhelming urge to throw Stark through a wall. 

“And you decided to wait three hours before calling me?” 

“It took us three hours to figure out where the fuck you were,” Stark snapped, and Bucky’s upper lip curled up over his teeth instinctively, a growl growing in his chest. 

“Not helpful,” Wilson said, stepping between them and looking annoyed. “I told you, you should’ve cleared out with the rest of the alphas, Stark.” 

“Nat got to stay!” 

“She actually gets along with him!” Wilson cried, flapping an arm in Bucky’s direction. A few bird themed puns popped into his head and he forced them down. 

Stark opened his mouth to reply and Bucky just cut him off. 

“Can I see him? As much fun as this conversation is. My mate is in heat and I’d like to help him through it.” 

Stark shared a look with Banner over his shoulder before taking a deep breath and switching the screen to a live video stream of Steve. 

Steve, in an impersonal room in the medbay, shivering and shaking on a twin bed with a blanket over his head and draped over his body, a big white bucket trapped between his knees. Bucky’s heart warmed at the bulky dark blue comforter, knowing someone must have grabbed it from their Brooklyn brownstone and knowing it was drenched in their combined scents. His eyes followed the clear thin tube leading from the IV, watching it tremble with Steve’s shaking. His poor boy, all worked up and suffering through it for hours without him. 

“Steve,” he whispered, pressing his fingertips against the screen. The audio chose that moment to turn on, a series of short, high whines crackling out the speakers. Something hot and possessive rose in Bucky’s chest and he found himself moving away from the screens before he knew what he was doing. That was his  _ mate,  _ his Stevie, crying out and desperate to be loved on and taken care of. 

“Where is he?” 

“He’s on one of the upper floors,” Stark said, folding his arms. “I moved him up there so no one could, ah, smell him.” 

That sweet smell of peaches and earthy charcoal. Twitching a little, Bucky rolled his shoulders and cracked his neck, feeling that tell-tale tension at the back of his neck. He was starting to fidget, clenching and releasing his fingers and feeling like he needed to bounce on the balls of his feet. God, Steve’s heat must be killing him if just knowing he was in heat was sending Bucky into rut. 

“Let’s get you to him,” Wilson said, wrinkling his nose a little at the burst of pheremones Bucky was producing. “Before you pop a knot right here.” 

“Give me at least a bit of credit, Wilson,” he snarked, sniffing and clapping his hands against his thighs, restless and desperate to see his mate. “Not all of us finish in seven minutes.” 

“Fuck, I knew he was gonna tell you about that. It wasn’t my fault, alright? Jesus, you come early  _ one time.”  _

“Mmm, can’t relate.”

They bickered the entire way up to Steve’s floor until the elevator opened to the lobby area, Buck’s words dying in his throat. He could smell Steve from here, sweet burnt sugar and peaches and so goddamn mouthwatering. 

“Down the hall, second door on your right.” Wilson coughed and pulled his shirt up over his nose. “Sorry, your boy smells good. Figured you wouldn’t want me sniffing around.” 

That- was extremely considerate. Bucky offered him a small smile before booking it to Steve’s room. 

Even if Stark hadn’t given him directions, Bucky would’ve had no issues finding Steve’s room, his scent flowing past what had to be supersoldier scent blockers, the walls, and probably a sealed medbay room. The closer he got, though, the more bitter that sugary scent turned, mixed with the desperate sourness of an unsatisfied and unhappy omega. God, his poor guy. 

The door to Steve’s room was, surprise, sealed and he only had to throw a look in the general direction of the ceiling before Friday slid the glass open for him. 

“Thanks,” he said quietly, not trusting his voice. Steve looked so broken and so small, curled in on himself with their blanket draped over his head. The room smelled like a rank mixture of slick and distressed hormones, like Steve’s caramelized sugar had been torched and left to burn. Which is kind of what Bucky felt like he’d done- left his guy to fend for himself during what was obviously a worse-than-supersoldier heat. 

“Go  _ away,  _ Sam,” Steve croaked as the doors slid closed behind Bucky. “I already told you, ‘m fine.” 

“Don’t smell fine, Stevie.” 

There was a small moment of silence before Steve tumbled off the bed, all cute and tangled in the blanket and tripping over himself in his desperation to get to his mate. 

“Hey, hey, it’s okay. I’m here, Stevie, right here.” He tugged the omega to his chest and let him scent him, soft little whines slipping between Steve’s lips as he hungrily nosed at Bucky’s scent glands. 

And then he noticed Steve was standing on his tiptoes to scent him instead of bending down. The hands holding tight onto his shoulders were thinner, too, delicate and long fingers leading to big palms and skinny, easily dislocating wrists. 

“Steve.” He stepped back, holding both arms out and backing into the door. This wasn’t- this couldn’t be right. 

Steve was  _ small,  _ the top of his head barely clearing Bucky’s shoulder, his thin frame drowning in a t-shirt Bucky recognized as one that used to be too small on him. He could hear the slight wheeze in Steve’s every breath, his chest skinny with a rattling heart that liked to skip beats; Bucky knew if he pushed up that shirt he could count the ribs just barely stretching that pale Irish skin. 

“What the hell happened?” Bucky whispered, pressing himself tight against the door. He could hurt Steve like this; he’d gotten too used to being on the same playing field with Steve, too used to the serum that filled him out and kept him nearly invincible. Steve frowned, shifting a little where he stood and wrapping his arms around his tiny little torso. They both picked up on the nervous, worried that started to sour his normally woodsy, metallic scent. 

“Something with the aliens that attacked,” Steve grumbled, rubbing a hand over an enormous purpling bruise on his scent glands. Bucky bristled at the sight. Of course they’d go for the most sensitive part of his body. “The queen got me with some weird goo shit and reversed the serum. Bruce doesn’t think it’s permanent, says it’ll probably go away once my body works through whatever she hit me with.” 

“Is it- are you okay?” Bucky slowly stepped forward and slid his right hand to the small of Steve’s back, trailing his fingers so gently up the curve of his spine. “Your back hurting?” 

Steve pulled a face and Bucky couldn’t help but snort. 

“It’s from the heat, too,” he whined, squirming closer to his alpha. “You gonna help me with that or am I gonna have to take Tony up on his offer for a bag of toys?” 

A snarl ripped from Bucky’s throat before he could stop it and he scooped Steve up- gently, of course, couldn’t risk hurting him- and depositing him on the bed. He grinned up at him, cocky, wiggling out of his big t-shirt and yanking down his slick soaked boxers while Bucky shucked his gear. 

“You mention Stark one more time when you’re dripping wet,” Bucky growled, tugging Steve to the edge of the bed by his ankles and kneeling on the floor so he was eye level with Steve’s sweet little hole. “And you can forget about getting knotted.” 

“Mmm, you wouldn’t do that to me, would ya, Buck?” Steve cooed, dropping his head back and tugging at his already swollen nipples. “You wouldn’t leave your omega hanging, would you?” 

“You’re such a little shit,” he grumbled, biting into the creamy skin of Steve’s thigh before nosing down the crease of his thigh and kissing his way between his pert little cheeks. Steve’s chatter, magically, vanished once Bucky started licking him open with wide, broad strokes. His baby was so wet already, slick smeared all the way down his crack and the inside of his shaking thighs. 

“So good, Buck,” he sighed, knocking his head back on the bed and shutting his eyes. Bucky growled low in his chest and maneuvered them a little so Steve’s knobby knees sat over his mismatched shoulders, freeing up some of the weight from his lower back. Steve’s scent turned from sour to sweet in seconds, breathy little moans pouring out of his lips as Bucky gently ate him out. It only took a little bit of prodding before two of Bucky’s metal fingers were pushing past Steve’s rim, sinking deep inside that wet heat to nudge his fingertips against Steve’s swollen prostate. 

Steve just managed to gasp out his mate’s name before he was coming, his back arching in one sweet curve as his little cock twitched and spurted ropes of pearly white come. Normally Bucky would keep going, keep wiggling his tongue and fingers against those bundles of nerves until Steve’s three second refractory period ended and he was rearing to go again. 

Now though? Now he slowly eased his fingers out, swirling his thumb around Steve’s slightly stretched rim to soothe the needy whine his omega let out. 

“Shh, honey,” he cooed, pressing hot, open mouthed kisses to Steve’s thighs. “You’re alright.” 

“Need more,” Steve grumbled, rubbing blearily at his eyes. Bucky tried not to think about how fragile he looked and focused instead on lazily lapping up the splattering of come across Steve’s flat little tummy. 

“Remember doing this before the war,” he murmured, gently kissing the soft pink head of Steve’s dick. It was so sweet and cute, laying soft and spent below his belly button. “Remember how gentle I hadta’ be.” 

Steve groaned and tried to shove his hole back towards Bucky’s mouth, greedy now that some of the edge had been taken off. 

“You couldn’t even present the first time we did this,” Bucky continued, grabbing Steve’s legs to settle him and shooting him an unimpressed look from between them. He knew his mate wasn’t the brightest, but did he really think he’d be able to bodily force Bucky to move the way he wanted? C’mon, Stevie. “Damn near broke that curvy little spine of yours trying.”

“You’re the worst,” Steve hissed, trying to pull Bucky’s hand up to tug at his nipples. 

“You’re the one that mated with me.” 

Steve ignored him and Bucky hated how fond that made him feel. 

“Do you have any idea how awful an unsatisfied heat is?” Steve asked, dramatically flopping back onto the bed. “How much it hurts finishing your cycle without a knot?” 

“Mmm, don’t think so,” Bucky rumbled, finally giving in and kissing up Steve’s bony chest. The blonde squirmed under him, still so sensitive, but kept running his mouth as Bucky sucked on his nipples. 

“Ahh, s’awful,” he groaned, hands grappling for two fistfuls of Bucky’s hair. “Aches and hurts for days after. You wouldn’t, fuck, wouldn’t leave me like that, would ya’, Buck? All sore and empty?” 

“Maybe I oughta,” Bucky mused, nuzzling his way to Steve’s bond mark and letting his teeth graze against it. “You’re so mouthy.” 

“Like you’re not the same way when you’re in rut,” Steve snapped, and Bucky couldn’t help grinning into the blondes neck. There was his sweet, nurturing little omega. 

“Mmm, but at least I’m sweet on you. You’re just mean.” 

Steve’s scoff quickly turned into a moan as Bucky shifted them again to press his lips to Steve’s, swallowing down all those breathy moans and cries. It only took a minute or two before Steve got antsy, thrusting his hips up in a desperate hunt for friction Bucky refused to give him. 

“C’mon, sweetheart, hands and knees,” he said, smacking one more kiss on Steve’s pretty pink lips before pulling back to shed the rest of his clothes. 

And, god, did Stevie present for him. The logical part of his brain knew presenting helped with the heat, helped ease the tight muscles in an omega’s lower back. Steve always described it like cracking a joint that’d been stiff for a while, or a good orgasm- satisfying and somehow just  _ right.  _ But the Bucky part of his brain worried about the stress on the delicate curve of Steve’s spine; he’d been sensitive at best before the serum, barely able to hold the presenting position before his crooked back was aching and throbbing. 

“So fuckin’ pretty, Stevie,” he growled, scooting up the bed to pepper kisses up Steve’s spine. “So open and ready for me.” 

“God, do you ever shut your trap?” Steve snarked, pushing back towards Bucky’s dick in a desperate attempt to get it inside him already. “Could’ve had me happy and knotted already if you’d just shut up.” 

“Ya know,” Bucky said casually, framing Steve’s skinny little waist with both hands and pushing inside him in one long unforgiving thrust. He couldn’t help but smirk at Steve’s high whine. “Ma always told me about how sweet and submissive omegas were. And I go and bond with the mouthiest little shit Brooklyn could’a cooked up.” 

Steve grumbled something that sounded like a bunch of swear words under his breath, grunting and burying his face in the blankets when Bucky finally started to move, just little rocking motions to ease the way until he could pull out fully without hurting Steve. 

“So good for me,” he groaned, pushing a hand softly between Steve’s shoulder blades so he was more or less laying flat on the bed. “Such a good little omega, taking your alphas cock so well. Like you were fucking made for it.” 

“I was,” Steve snarked, his voice somewhat muffled by the bunch of comforter he’d shoved between his teeth to keep from crying out as Bucky sped up his thrusts. “S’kinda what being an omega’s all about.” 

“Just take the compliment, Rogers.” Bucky pinched the soft swell of Steve’s ass just to hear him squak. And maybe a little to feel the way Stevie clenched down hard on his cock. “Didn’t your mama teach you any manners?” 

“You have managed,” Steve panted, letting go of his bite on the comforter in favor of digging his forehead into the mattress. “To mention not only your own, but also my ma in the last five minutes. All while- ahh, fuck, right there- balls deep in my asshole.” 

“Your point?” Bucky accentuated his question with a series of sharp, pointed thrusts. 

“Fuckin’- stop it, is my point.” 

Just to be a prick, Bucky slowed his hips, pulling out until just the flared head of his dick was still seated inside his mate. 

“What?” he cooed innocently when Steve whined and tried to push back onto his cock. “You said to stop.” 

“I hate you,” Steve growled, still trying valiantly to work himself up and down on Bucky’s length despite the grip the brunette had on his skinny hips. “Reverse the bond mark. I, fuck, I want a divorce. Sadism is one thing but this- this is just cruel.” 

“It’s fun seeing you all worked up like this.” Bucky pressed a metal thumb into the sweet dip of Steve’s back, that shallow dimple right above his ass, and dragged it down to where his own cock was holding Steve open. “Can’t blame a guy for enjoying the view.” 

Steve snarled then, teased and strung out on hormones and whatever alien shit he’d gotten hit with, and Bucky had to take pity on him. A snarl was the closest thing he was going to get to Steve Rogers begging, and he’d long learned to pick his battles in the bedroom. 

  
  


They didn’t leave the med bay for three days. Stark had arranged food and water to be sent to them- via a very polite Beta intern that blushed and stammered as she unloaded the protein bars and shake mixes onto a table- and Bucky managed to sneak out to snag any and all pillows and blankets from the nearby rooms. Steve was thoroughly nested and sated until he rolled over the morning of the fourth day and bashed his elbow into Bucky’s face. 

“S’ry,” he grunted, not even opening his eyes as Bucky jerked awake with a cry of pain. Fucker probably broke his nose. 

“You sound real sorry.” He wiped an arm under his nose, checking for blood, and paused when he saw Steve’s toes peeking out at the edge of the bed. “Hey, uh, Stevie?” 

“Wha’?” 

A pair of cold metal fingers dug into the arch of his foot, making him jerk around wildly and almost kick his mate in the face. 

“What the fuck was that for?” he growled, sitting up now, flushed and bedwarm. He pouted, fucking put out his lower lip, the dramatic fuck, and pulled a blanket up to wrap around his shoulders. 

Shoulders that were back to being as wide as a brick shit house. 

“You seem to be feeling better.”

It only took Steve about three seconds to check himself out, wiggle around a little with that crease between his eyebrows, and reach for the stack of clean clothes that’d gone untouched for three days. 

“Where are you going?” 

“I need to debrief with… the team…?” He paused with one leg in a pair of joggers, frowning at Bucky’s raised eyebrow. 

“Or,” he said, standing up and stretching so his spine cracked all the way down. Fuck that was a good one. “We could go home. Could make you a proper nest, stay holed up in there till Monday. How’s that sound, huh?” If there was a bit of sing song in his voice, and if he reached to rub Steve’s hipbones with his thumbs, cooing just a little, who could blame him? It’d been ages since he’d had non-heat related time off with his fella, and Steve had just been through a mild crisis. They could probably both use a couple of days off. “C’mon, Stevie, let’s put the couch cushions on the floor and turn the Dodger’s on. Make a weekend of it.” He grinned wickedly. “Maybe see if we can break more of the furniture.” 

Steve’s cheeks went pink, his blush starting to speckle his upper chest, but he rolled his eyes. 

“If you hated the bed frame so much, why didn’t you tell me in the store?” 

He hummed and nuzzled forward to scent his mate, worming close and tugging his fella further into his arms. 

“You were so excited about it,” he murmured, biting just a little on Steve’s neck just to hear him groan. “And it gives me something to work towards when I’m fucking you.” 

“Jesus Christ,” Steve murmured, and Bucky could just smell him starting to slick up. He grinned. “Yeah, yeah, shut up and take me home.” 

Bucky had never been happier to take his best guy back to Brooklyn. 

**Author's Note:**

> ¯\\_(ツ)_/¯  
I wrote this in one night in a frenzy and it was on my laptop still the next day so I posted it.   
Feel free to like or leave comments! Feedback is always appreciated!


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